Why does my composition only play when i am on 15 fps?

I have AE 22. When i play the preview/playback in a composition that isn’t 15 fps, the program starts lagging and slowing down. It happens both if i add media and if i don’t, does anyone know what the problem might be and how to fix it? I wanna use 18 fps or more but even then it gives me problems and doesn’t load as it should